1. Field of the Invention
The present invention relates to a touch lever closing mechanism of a touch lever type dimensions measuring apparatus.
2. Prior Art
An arrangement of a conventional touch lever type dimensions measuring apparatus will be described with reference to FIG. 5.
Designated at 2 is a fixed receiver having a V-shaped recess (hereinafter referred to as a V-recessed receiver), 3A and 3B are position detectors, 9 is a work outer diameter of which is measured, 10A and 10B are touch levers, 11 is actuators and 12 is a sensor. The work 9 is conveyed between the two touch levers 10A and 10B so that the touch levers 10A and 10B clamp the work 9 and measure the outer diameter of the work 9. If the work 9 is formed of a soft material such as aluminium, the work 9 is abraded by the touch levers 10A and 10B when the work 9 is put on the fixed V-recessed receiver 2, whereby the work 9 is liable to be damaged. To prevent such damage, the touch levers 10A and 10B should be opened before the work 9 is put on the fixed V-recessed receiver 2.
An operation of the actuators 11 will be described with reference to FIGS. 6 and 7.
Designated at 5 is connecting bars, 13 is fulcrums. FIG. 6 shows the operation of the actuators 11 before the work 9 is put on the fixed V-recessed receiver 2. The actuators 11 are operated so that the touch levers 10A and 10B are opened. When the actuators 11 move in the direction of the arrow, the touch levers 10A and 10B, which are connected to the connecting bars 5, are turned about the fulcrums 13 and are opened outside.
When the work 9 is put on the fixed V-recessed receiver 2, as illustrated in FIG. 5, the sensor 12 detects the work 9 and issues a signal instructing to close the touch levers 10A and 10B. The actuators 11 are driven, upon reception of the signal from the sensor 12, to close the touch levers 10A and 10B. Accordingly, the touch levers 10A and 10B clamp the work 9 so that the outer diameter of the work 9 is measured by the position detectors 3A and 3B. The position detectors 3A and 3B are of each differential transformer type.
The conventional touch lever closing mechanism requires the actuators 11 for opening and closing the touch levers 10A and 10B and also requires an electric sequential control for supplying the signal from the sensor 12 to the actuators 11 when the sensor 12 detected the work 9.